This invention is generally directed to developer compositions, and more specifically, the present invention relates to developer compositions with coated carrier components, or coated carrier particles that can be prepared by, for example, the selection of two latexes, which are wet blended, followed by coating on a carrier core and drying. More specifically, the present invention relates to carrier compositions comprised of a core, and thereover a polymer, such as a polymer of polymethylmethacrylate co-methacrylic acid generated from two dissimilar latexes, that is latexes that contain the same monomer, and wherein there is generated a polymer with a high weight average molecular weight, such as from about 1,000,000 to about 8,000,000 and a polymer with a low weight average molecular weight of, for example, from about 500,000 to about 750,000. The carrier may include the polymer coating generated in admixture with other suitable polymers, and more specifically, with a second polymer, such as a fluoropolymer, polymethylmethacrylate, poly(urethane), especially a crosslinked polyurethane, such as a poly(urethane)polyester and the like, and moreover, the copolymer coating may contain a conductive component, such as carbon black, and which conductive component is preferably dispersed in the polymer coating. With the conductive component, there can be enabled carriers with increased developer triboelectric response at relative humidities of from about 20 to about 90 percent, improved image quality performance, excellent high conductivity ranges of from about 10−10 to about 10−7 (ohm-cm)−1, and the like.
Advantage associated with the carriers of the present invention include efficient carrier coating processes with substantially no exotherms on full scale up; a high triboelectrical charge, for example a carrier tribo range of from about a plus (positive charge) 25 to about 75, and preferably from about a positive 30 to about a positive 65 microcoulombs per gram. The carrier particles of the present invention can be selected for a number of different imaging systems and devices, such as xerographic copiers and printers, inclusive of high speed color xerographic systems, printers, digital systems, a combination of xerographic and digital systems, and wherein colored images with excellent and substantially no background deposits are achievable. Developer compositions comprised of the carrier particles illustrated herein are generally useful in electrostatographic or electrophotographic imaging systems, especially xerographic imaging and printing processes, and digital processes. Additionally, the invention developer compositions comprised of substantially conductive carrier particles are useful in imaging methods wherein relatively constant conductivity parameters are desired. Furthermore, in the aforementioned imaging processes the triboelectric charge on the carrier particles can be preselected, which charge is dependent, for example, on the polymer composition and dispersant component applied to the carrier core, and optionally the type and amount of the conductive component selected.